patch 8.1.0421: MS-Windows: Ruby path is wrong for Ruby 1.9 and later

Problem:    MS-Windows: Ruby path is wrong for Ruby 1.9 and later.
Solution:   Let -I argument depend on Ruby version. (Ken Takata, closes #3461)

Author: brammool

src/Make_cyg_ming.mak

@@ -475,9 +475,10 @@ ifeq (19, $(word 1,$(sort 19 $(RUBY_VER))))
 RUBY_19_OR_LATER = 1
 endif
 
-RUBYINC = -I $(RUBY)/lib/ruby/$(RUBY_API_VER_LONG)/$(RUBY_PLATFORM)
 ifdef RUBY_19_OR_LATER
-RUBYINC += -I $(RUBY)/include/ruby-$(RUBY_API_VER_LONG) -I $(RUBY)/include/ruby-$(RUBY_API_VER_LONG)/$(RUBY_PLATFORM)
+RUBYINC = -I $(RUBY)/include/ruby-$(RUBY_API_VER_LONG) -I $(RUBY)/include/ruby-$(RUBY_API_VER_LONG)/$(RUBY_PLATFORM)
+else
+RUBYINC = -I $(RUBY)/lib/ruby/$(RUBY_API_VER_LONG)/$(RUBY_PLATFORM)
 endif
 ifeq (no, $(DYNAMIC_RUBY))
 RUBYLIB = -L$(RUBY)/lib -l$(RUBY_INSTALL_NAME)

src/Make_mvc.mak

@@ -1136,7 +1136,7 @@ RUBY_INSTALL_NAME = mswin32-ruby$(RUBY_API_VER)
 CFLAGS = $(CFLAGS) -DFEAT_RUBY
 RUBY_OBJ = $(OUTDIR)\if_ruby.obj
 !if $(RUBY_VER) >= 19
-RUBY_INC = /I "$(RUBY)\lib\ruby\$(RUBY_API_VER_LONG)\$(RUBY_PLATFORM)" /I "$(RUBY)\include\ruby-$(RUBY_API_VER_LONG)" /I "$(RUBY)\include\ruby-$(RUBY_API_VER_LONG)\$(RUBY_PLATFORM)"
+RUBY_INC = /I "$(RUBY)\include\ruby-$(RUBY_API_VER_LONG)" /I "$(RUBY)\include\ruby-$(RUBY_API_VER_LONG)\$(RUBY_PLATFORM)"
 !else
 RUBY_INC = /I "$(RUBY)\lib\ruby\$(RUBY_API_VER_LONG)\$(RUBY_PLATFORM)"
 !endif

src/version.c

@@ -794,6 +794,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    421,
 /**/
     420,
 /**/